Plyometric Landings on Land and in Waist-Deep Water: Comparison Between Young and Middle-Aged Adults

The purpose of this study was to compare dynamic stability and landing kinetics, on land and in water, between young and middle-aged adults performing plyometric exercises. Twenty adults were asked to volunteer: Young = 24.40 ± 2.63 years, n = 10 and middle-aged = 46.80 ± 3.05 years, n = 10. Participants performed three plyometric exercises (countermovement jump, squat jump, and drop landing) on land and in waist-deep water. Dynamic stability was assessed during landing for each exercise using a time to stabilization (TTS) paradigm. Kinetic measures included time to peak force, peak force, rate of force development (RFD), and impulse. Data were collected via a waterproof force plate positioned on an adjustable-depth pool floor and analyzed with a 2 (age) X 6 (condition) repeated measures ANOVA. Results revealed TTS was greater on land (1.45 ± 0.12s) than in water (1.35 ± 0.12s) for two jumps (p = 0.01). Peak force, RFD, and impulse were greater on land (33%-36%) (p \u3c 0.01). Time to peak force was lower (20%), while normalized peak force (15%) and RFD were greater (28%), in the middle-aged compared to the young group (p = 0.04). Results indicate that young and middle-aged adults display improved dynamic stability and are exposed to lower absolute impact forces in water. The effect of age indicates middle-aged participants tend to display greater loading rates and peak forces when compared to the younger group, suggesting landing patterns that may be harmful

Resource competition drives an invasion-replacement event among shrew species on an island

Invasive mammals are responsible for the majority of native species extinctions on islands. While most of these extinction events will be due to novel interactions between species (e.g. exotic predators and naive prey), it is more unusual to find incidences where a newly invasive species causes the decline/extinction of a native species on an island when they normally coexist elsewhere in their overlapping mainland ranges. We investigated if resource competition between two insectivorous small mammals was playing a significant role in the rapid replacement of the native pygmy shrew Sorex minutus in the presence of the recently invading greater white-toothed shrew Crocidura russula on the island of Ireland. We used DNA metabarcoding of gut contents from >300 individuals of both species to determine each species' diet and measured the body size (weight and length) during different stages of the invasion in Ireland (before, during and after the species come into contact with one another) and on a French island where both species have long coexisted (acting as a natural ‘control’ site). Dietary composition, niche width and overlap and body size were compared in these different stages. The body size of the invasive C. russula and composition of its diet changes between when it first invades an area and after it becomes established. During the initial stages of the invasion, individual shrews are larger and consume larger sized invertebrate prey species. During later stages of the invasion, C. russula switches to consuming smaller prey taxa that are more essential for the native species. As a result, the level of interspecific dietary overlap increases from between 11% and 14% when they first come into contact with each other to between 39% and 46% after the invasion. Here we show that an invasive species can quickly alter its dietary niche in a new environment, ultimately causing the replacement of a native species. In addition, the invasive shrew could also be potentially exhausting local resources of larger invertebrate species. These subsequent changes in terrestrial invertebrate communities could have severe impacts further downstream on ecosystem functioning and services

The Cycladic Blueschist Unit on Tinos, Greece: Cold NE Subduction and SW Directed Extrusion of the Cycladic Continental Margin Under the Tsiknias Ophiolite

High pressure‐low temperature (HP‐LT) metamorphic rocks structurally beneath the Tsiknias Ophiolite make up the interior of Tinos Island, Greece, but their relationship with the overlying ophiolite is poorly understood. Here, new field observations are integrated with petrological modeling of eclogite and blueschists to provide new insight into their tectonothermal evolution. Pseudomorphed lawsonite‐, garnet‐, and glaucophane‐bearing schists exposed at the highest structural levels of Tinos (Kionnia and Pyrgos Subunits) reached ~22–26 kbar and 490–520°C under water‐saturated conditions, whereas pseudomorphed lawsonite‐ and aegirine‐omphacite bearing eclogite reached ~20–23 kbar and 530–570°C. These rocks are separated from rocks at deeper structural levels (Sostis Subunit) by a top‐to‐SW thrust. The Sostis Subunit records P‐T conditions of ~18.5 kbar and 480–510°C and is overprinted by pervasive top‐to‐NE shearing that developed during exhumation from (M1) blueschist to (M2) greenschist facies conditions of ~7.3 ± 0.7 kbar and 536 ± 16°C. These P‐T‐D relationships suggest that the Cycladic Blueschist Unit represents a discrete series of tectonometamorphic subunits that each experienced different tectonic and thermal histories. These subunits were buried to variable depths and sequentially extruded toward the SW from a NE dipping subduction zone. The difference in age and P‐T conditions between the HP‐LT rocks and the overlying metamorphic sole of the Tsiknias Ophiolite suggests that this NE dipping subduction zone was active between circa 74 and 46 Ma and cooled at a minimum rate of ~1.2–1.5°C/km/Myr prior to continent‐continent collision between Eurasia and Adria/Cyclades

The Outer Halo Globular Clusters of M31

We present Keck/HIRES spectra of 3 globular clusters in the outer halo of M31, at projected distances beyond ~80 kpc from M31. The measured recession velocities for all 3 globular clusters confirm their association with the globular cluster system of M31. We find evidence for a declining velocity dispersion with radius for the globular cluster system. Their measured internal velocity dispersions, derived virial masses and mass-to-light ratios are consistent with those for the bulk of the M31 globular cluster system. We derive old ages and metallicities which indicate that all 3 belong to the metal-poor halo globular cluster subpopulation. We find indications that the radial gradient of the mean metallicity of the globular cluster system interior to 50 kpc flattens in the outer regions, however it is still more metal-poor than the corresponding field stars at the same (projected) radius.Comment: 6 pages, 4 figures, 3 tables. Accepted for publication in MNRAS Letter

The History and Prehistory of Natural-Language Semantics

Contemporary natural-language semantics began with the assumption that the meaning of a sentence could be modeled by a single truth condition, or by an entity with a truth-condition. But with the recent explosion of dynamic semantics and pragmatics and of work on non- truth-conditional dimensions of linguistic meaning, we are now in the midst of a shift away from a truth-condition-centric view and toward the idea that a sentence’s meaning must be spelled out in terms of its various roles in conversation. This communicative turn in semantics raises historical questions: Why was truth-conditional semantics dominant in the first place, and why were the phenomena now driving the communicative turn initially ignored or misunderstood by truth-conditional semanticists? I offer a historical answer to both questions. The history of natural-language semantics—springing from the work of Donald Davidson and Richard Montague—began with a methodological toolkit that Frege, Tarski, Carnap, and others had created to better understand artificial languages. For them, the study of linguistic meaning was subservient to other explanatory goals in logic, philosophy, and the foundations of mathematics, and this subservience was reflected in the fact that they idealized away from all aspects of meaning that get in the way of a one-to-one correspondence between sentences and truth-conditions. The truth-conditional beginnings of natural- language semantics are best explained by the fact that, upon turning their attention to the empirical study of natural language, Davidson and Montague adopted the methodological toolkit assembled by Frege, Tarski, and Carnap and, along with it, their idealization away from non-truth-conditional semantic phenomena. But this pivot in explana- tory priorities toward natural language itself rendered the adoption of the truth-conditional idealization inappropriate. Lifting the truth-conditional idealization has forced semanticists to upend the conception of linguistic meaning that was originally embodied in their methodology

Effects of Trophic Skewing of Species Richness on Ecosystem Functioning in a Diverse Marine Community

Widespread overharvesting of top consumers of the world’s ecosystems has “skewed” food webs, in terms of biomass and species richness, towards a generally greater domination at lower trophic levels. This skewing is exacerbated in locations where exotic species are predominantly low-trophic level consumers such as benthic macrophytes, detritivores, and filter feeders. However, in some systems where numerous exotic predators have been added, sometimes purposefully as in many freshwater systems, food webs are skewed in the opposite direction toward consumer dominance. Little is known about how such modifications to food web topology, e.g., changes in the ratio of predator to prey species richness, affect ecosystem functioning. We experimentally measured the effects of trophic skew on production in an estuarine food web by manipulating ratios of species richness across three trophic levels in experimental mesocosms. After 24 days, increasing macroalgal richness promoted both plant biomass and grazer abundance, although the positive effect on plant biomass disappeared in the presence of grazers. The strongest trophic cascade on the experimentally stocked macroalgae emerged in communities with a greater ratio of prey to predator richness (bottom-rich food webs), while stronger cascades on the accumulation of naturally colonizing algae (primarily microalgae with some early successional macroalgae that recruited and grew in the mesocosms) generally emerged in communities with greater predator to prey richness (the more top-rich food webs). These results suggest that trophic skewing of species richness and overall changes in food web topology can influence marine community structure and food web dynamics in complex ways, emphasizing the need for multitrophic approaches to understand the consequences of marine extinctions and invasions

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Invading and expanding : range dynamics and ecological consequences of the Greater White-Toothed Shrew (Crocidura russula) invasion in Ireland

Establishing how invasive species impact upon pre-existing species is a fundamental question in ecology and conservation biology. The greater white-toothed shrew (Crocidura russula) is an invasive species in Ireland that was first recorded in 2007 and which, according to initial data, may be limiting the abundance/distribution of the pygmy shrew (Sorex minutus), previously Ireland’s only shrew species. Because of these concerns, we undertook an intensive live-trapping survey (and used other data from live-trapping, sightings and bird of prey pellets/nest inspections collected between 2006 and 2013) to model the distribution and expansion of C. russula in Ireland and its impacts on Ireland’s small mammal community. The main distribution range of C. russula was found to be approximately 7,600 km2 in 2013, with established outlier populations suggesting that the species is dispersing with human assistance within the island. The species is expanding rapidly for a small mammal, with a radial expansion rate of 5.5 km/yr overall (2008–2013), and independent estimates from live-trapping in 2012–2013 showing rates of 2.4–14.1 km/yr, 0.5–7.1 km/yr and 0–5.6 km/yr depending on the landscape features present. S. minutus is negatively associated with C. russula. S. minutus is completely absent at sites where C. russula is established and is only present at sites at the edge of and beyond the invasion range of C. russula. The speed of this invasion and the homogenous nature of the Irish landscape may mean that S. minutus has not had sufficient time to adapt to the sudden appearance of C. russula. This may mean the continued decline/disappearance of S. minutus as C. russula spreads throughout the island

Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

• Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. • Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed-effects models were used to disentangle sources of variation in Rdark. • Area-based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdark at a standard T (25°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher in herbs than in woody plants. • The results highlight variation in Rdark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdark in terrestrial biosphere models (TBMs) and associated land-surface components of Earth system models (ESMs)